More Carnage in Syria

Secretary of State John Kerry and Staffan de Mistura, a United Nations envoy, aretrying again to revive the cease-fire in Syria that has collapsed in significant parts of the country, including Aleppo. The goal is urgent, but the diplomacy will not have a chance if Russia will not, or cannot, persuade its ally Bashar al-Assad, Syria’s president, to stop using his air force to bomb opposition targets.

Few expected the cease-fire, which was brokered two months ago by the United States and Russia, to last as long as it did. It gave many civilians a respite from a civil war that has reportedly killed up to 470,000 people over five years, driven millions from their homes, overwhelmed Europe with refugees and allowed the Islamic State and other terrorists to gain control of swaths of the country. But in recent weeks the fighting has resumed, particularly in Aleppo, where more than 200 people have died in the last week, most in areas held by anti-Assad rebels.

On Tuesday, rebel fighters began an assault on the northern part of the divided city, including an attack on a maternity hospital, according to state media and video from the scene. But most of the renewed fighting comes from government forces, which have airplanes and helicopters to drop barrel bombs and recently struck a hospital and three clinics in Aleppo.

Both sides have shown increasing disregard for international law that says attacks on civilians and medical facilities are war crimes. The United Nations Security Council unanimously passed a resolution Tuesday condemning the attacks after Dr. Joanne Liu, the president of Doctors Without Borders, said, “Seeking or providing health care must not be a death sentence.”

Meanwhile, in a flurry of diplomacy aimed at a cease-fire that covers Aleppo, Mr. de Mistura met Mr. Kerry on Monday and Russia’s foreign minister, Sergey Lavrov, the next day. Mr. Lavrov and, later in Washington, Mr. Kerry expressed hope that their two countries were on the verge of a cease-fire agreement.

Russia’s president, Vladimir Putin, who intervened militarily last September to save Mr. Assad from rebel advances, may be up to duplicitous tricks again. Last month, Russia moved heavy artillery into position outside Aleppo, raising fresh questions about its intentions. Despite a commitment to work with America in peace talks, Russia has failed to get Mr. Assad to compromise on the key issue of a political transition to a new, inclusive government.

The Russians clearly have influence with Mr. Assad, as the two months of relative calm demonstrated. One important test is whether they persuade Mr. Assad to stop blocking food and medical deliveries to civilians in the Damascus suburbs. The United States, Saudi Arabia and Qatar, which support various opposition groups, also must be willing to withhold weapons, intelligence and other assistance if the groups refuse to end the fighting.

Speaking in Geneva, Mr. Kerry said the Americans and Russians would strengthen an office there that monitors the cease-fire. The two sides are also considering ways to map the locations of government and opposition forces so they can be distinguished from the Nusra Front, an affiliate of Al Qaeda that is not part of the cease-fire, an American official said.

Both measures, like the broader issue of peace in Syria, depend heavily on Mr. Putin’s cooperation. President Obama and Mr. Kerry must be willing to pressure him to do what is needed to stop the bloodshed.